fix(typeahead): accessibility fixes

[YusefOuda]

• Adds role=combobox and sets aria-controls instead of aria-owns on typeahead.
• Ensure activeChangeEvent is fired when active item changes by using setter

Fixes #6468, #6647

PR Checklist

Before creating new PR, please take a look at checklist below to make sure that you've done everything that needs to be done before we can merge it.

• read and followed the CONTRIBUTING.md guide.
• built and tested the changes locally.
• added/updated tests.
• added/updated API documentation.
• added/updated demos.

[coliff]

Great PR! Hope to see this merged.

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.78%. Comparing base (e77c928) to head (874fa16).
⚠️ Report is 33 commits behind head on development.

Files with missing lines	Patch %	Lines
src/typeahead/typeahead-container.component.ts	81.25%	3 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           development    #6791      +/-   ##
===============================================
+ Coverage        76.60%   77.78%   +1.18%     
===============================================
  Files              317      318       +1     
  Lines            10748    11094     +346     
  Branches          2866     3081     +215     
===============================================
+ Hits              8233     8629     +396     
+ Misses            2514     2463      -51     
- Partials             1        2       +1     

Files with missing lines	Coverage Δ
src/typeahead/typeahead.directive.ts	86.52% <100.00%> (+1.45%)	⬆️
src/typeahead/typeahead-container.component.ts	83.91% <81.25%> (+6.50%)	⬆️

... and 77 files with indirect coverage changes

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